SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '386e31681b341e10b2bac2f17b785057f7fe0ec3c4b36012d978d20ffae82246' 
  AND token = 'dUJUQryrskWblAq/2ntBeYPtT7aTIcDXIbEH+XBWKDo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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