SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f968510e2324be99725af51abdd3091b08ea971a73124e98c25adad3b308a5d1' 
  AND token = '1FJ2p0HxSPv58rulo0jGMhhk9LZHkm3SFUOwX49m3Ds=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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