SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c53e5713f19a1923489d3bd3073c25aa651a5ef231e5189eed358e7fbf3fc48e' 
  AND token = 'xS7HsI/UQpNPFmVJO6iiZ1JMuGWMbBSMx6T7RKvFDoQ=' 
  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"
    }
  }
}