SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f15d3d59d55de485367da8eff51cecd379ea90caa75d602547b0fbbd9cc465b4' 
  AND token = 'HewVtS7wSjYUlnqry2GafIqLsxAPfVBQTeeADYWSECQ=' 
  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"
    }
  }
}