SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '94f742b18a4339600b3abac7d4ed3c98ff375b9dd6d44ce5f114a47c4ba46748' 
  AND token = 'aMnM4onojeUQJALiCMpjZzzGlPc3aKeZ0crLnByixCg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}