SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b4078e58fad9862c6738cf58b2f985cce0dffe13b1b6b20aef0df4b1a82b9fe1' 
  AND token = 'aJAGZGNq8xh2wHEQ+muoMmEIQIa1aYA2//VvhB+2YBk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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