SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fce5d48b37c55a784099a986f837ca22809c6ab50f403e2159a9e5c6b2317767' 
  AND token = 'o3wCsRMpBoXA1ewEWu8tN/+vyNW9I9mNxKc25ovLrhs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}