SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b8f19b4c55fbe62e2c01a09f06526ac948884092f0801563f9f2a93148d05a89' 
  AND token = 'IooVWHUjbHW5Muxo6LMzlPWMCr/1LThPCtK3s8W1D8I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}