SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c786c11a9dacff0bd9cc8146d1a8d013f98964a8f993823a593f8a1dbd35eefb' 
  AND token = 'BjuFPFXxkAh/LNxOgcTwsOEMERlQohP/JgO2GhYkolI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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