SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fe8daf94447dbeaa38d753f772c814fce165a68469f2d1a0935e1657d16fc7a3' 
  AND token = 'RDaM//nRGtTlJcjNQU2DfcIxZJhR2Qpf3OtjjeoR8Go=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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