SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b9a04db5627595f2cbc53775507edf8abd108bdb4303f185ae27d33538cda37b' 
  AND token = 'jtIZACkAgMJszW2w1JPDprZIvCUNCDaw3Xss0gQBsw8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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